ac73b73c16
Since C++11, the C++ standard has a forward progress guarantee [intro.progress], so all such functions must have the `mustprogress` requirement. In addition, from C11 and onwards, loops without a non-zero constant conditional or no conditional are also required to make progress (C11 6.8.5p6). This patch implements these attribute deductions so they can be used by the optimization passes. Differential Revision: https://reviews.llvm.org/D86841
61 lines
1.4 KiB
C++
61 lines
1.4 KiB
C++
// RUN: %clang_cc1 -O1 -disable-llvm-passes -emit-llvm %s -o - -triple=x86_64-linux-gnu -verify
|
|
// RUN: %clang_cc1 -O1 -disable-llvm-passes -emit-llvm %s -o - -triple=x86_64-linux-gnu | FileCheck %s
|
|
|
|
void wl(int e){
|
|
// CHECK-LABEL: define{{.*}}wl
|
|
// CHECK: br {{.*}} !prof !6
|
|
while(e) [[likely]] ++e;
|
|
}
|
|
|
|
void wu(int e){
|
|
// CHECK-LABEL: define{{.*}}wu
|
|
// CHECK: br {{.*}} !prof !10
|
|
while(e) [[unlikely]] ++e;
|
|
}
|
|
|
|
void w_branch_elided(unsigned e){
|
|
// CHECK-LABEL: define{{.*}}w_branch_elided
|
|
// CHECK-NOT: br {{.*}} !prof
|
|
// expected-warning@+2 {{attribute 'likely' has no effect when annotating an infinite loop}}
|
|
// expected-note@+1 {{annotating the infinite loop here}}
|
|
while(1) [[likely]] ++e;
|
|
}
|
|
|
|
void fl(unsigned e)
|
|
{
|
|
// CHECK-LABEL: define{{.*}}fl
|
|
// CHECK: br {{.*}} !prof !6
|
|
for(int i = 0; i != e; ++e) [[likely]];
|
|
}
|
|
|
|
void fu(int e)
|
|
{
|
|
// CHECK-LABEL: define{{.*}}fu
|
|
// CHECK: br {{.*}} !prof !10
|
|
for(int i = 0; i != e; ++e) [[unlikely]];
|
|
}
|
|
|
|
void f_branch_elided()
|
|
{
|
|
// CHECK-LABEL: define{{.*}}f_branch_elided
|
|
// CHECK-NOT: br {{.*}} !prof
|
|
for(;;) [[likely]];
|
|
}
|
|
|
|
void frl(int (&&e) [4])
|
|
{
|
|
// CHECK-LABEL: define{{.*}}frl
|
|
// CHECK: br {{.*}} !prof !6
|
|
for(int i : e) [[likely]];
|
|
}
|
|
|
|
void fru(int (&&e) [4])
|
|
{
|
|
// CHECK-LABEL: define{{.*}}fru
|
|
// CHECK: br {{.*}} !prof !10
|
|
for(int i : e) [[unlikely]];
|
|
}
|
|
|
|
// CHECK: !6 = !{!"branch_weights", i32 2000, i32 1}
|
|
// CHECK: !10 = !{!"branch_weights", i32 1, i32 2000}
|